Builder := Object clone
Builder forward := method(
    writeln("<", call message name, ">")
    call message arguments foreach(
        arg,
        content := self doMessage(arg);
        if(content type == "Sequence", writeln(content)))
    writeln("</", call message name, ">")
)

Builder ul(
    li("Ruby"),
    li("Python"),
    li("JavaScript")
)
